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UNITED STATES PATENT EEicE.

JOSEPH E. LOCKlVOOD, OF DETROIT, MICHIGAN, ASSIGNOR OF ONE-HALF TOCHARLES P. LARNED, OF SAME PLACE.

GALVANOM ETER.

SPECIFICATION forming part of Letters Patent No. 414,422, dated November5, 1889:

Application filed February 5, 1889. Serial No. 298,757. (No model.)

To all whom it may concern.-

Be it known that I, J OSEPH E. LOCKWOOD,

a citizen of the United States, residing at Detroit, county of Wayne,State of Michigan, have invented a certain new and useful Improvement inAmmeters and Polarity-Indicators; and I declare the following to be afull, clear, and exact description of the invention, such as will enableothers skilled in the art to which it pertains to make and use the same,reference being had to the accompanying drawings, which form a part ofthis specification.

In the drawings, Figure l is a perspective View of an apparatusembodying my invention. Fig. 2 is a perspective view of the same withthe case removed and a section broken away to illustrate theconstruction.

It is the purpose of my invention to produce a simple and eificientmechanism for use more particularly with electric-lightin g apparatusadapted to indicate at a glance from any point near at hand or at adistance therefrom the direction of the current, the number of amperes,and showing at a glance how near the current is to the normal, andwhether it is short or in excess of the normal.

In carrying out my invention, A represents a hollow vertical core,preferably of brass or other diamagnetic material, upon which is woundhorizontally a helix of insulated wire.

B is a horizontal steel magnetic needle adjusted within the core andsupported by a pivot-shaft B.

B is a long index-arm projecting vertically downward at right angles tothe needle B. Upon this arm is a weight I), made adjustable up and downupon the shaft.

0 is an ampere-scale with the O or neutral point at the middle. Upon oneside thebackground is of a different shade or color from that on theother side of the said neutral point. the right half maybe white,indicating all right, while the left half may be red, the universaldanger-signal, indicating that some thing is wrong. The index-pointer ispreferably darkened--as, for instance, it may be black. Its position istherefore clearly apparent, even at a great distance away. Upon theampere-scale, at the neutral point, I pro- Thus, for instance, thebackground of vide a heavy dark line or dart D, and at the proper pointsat the right and left T place prominent darts or indices D D markingthese points on the scale, which indicate the normal current for theline upon which the apparatus is employed.

E E represent binding-posts for the linewire terminals. They arepreferably brought nearly together at e, so as to be readily united orelectrically connected by any suitable means-as, for instance, by a plugE and for convenience I locate the plug adjacent thereto in a suitablerest or orifice in the frame, as shown in 1.

F F represent metallic connecting straps or links, which, by the screwsF are caused to unite the binding-posts E E with the immediate terminalsf f of the instrument proper. So, also, I prefer to make .the baseboardaof the instrument proper entirely separate'from the base-hoard 0/ ofthe terminals E E, so that by uniting said latter terminals by the plugE the screws F may be removed and the instrument disconnected withoutdisturbing the line or its terminals.

The operation of the device will now be understood. It is connected intothe circuit for which it is designed-as, for instance, into an arc-lightcircuit. The darts D and D are at the proper points on the scaleas,forinstance, at the ten-ampere graduations, that being the normal currentfor the line. Now, when the current is started, the tendency of theneedle B to assume a vertical position at right angles with thedirection of the wire in the helix causes the index-pointer B to move tothe right or left, according to the direction of the current on the mainline. If it moves to the right over the white field, it indicates thatthe current has its proper direction. So, also, its relative positionwith respect to the dark middle and side darts will show at a glancefrom along distance off just about the indicated amperage. So, again, asthe current approaches its normal, the position of the indexpointer withrespect to the normal-current dart D will show with great distinctnessfor a great distance the slightest variation to the right or left otthedart, and so indicate whether it is slightly too great or too little.Should the index-pointer start off to the left over the itself may beconnected into the line in reverse order. In any event, he is at onceput on his inquiry to discover the difficulty and correct the same. Theinstrument standing vertically, its scale and pointer can readily beseen at a distance. If the attendant desires to calibrate a series ofinstruments so they all have a uniform reading, he needs simply to plugbetween the terminals E E, remove the screws F and then connect theseveral instruments together in series.

If for any reason the needle 13 loses a part of its magnetism andso-acts sluggishly, the weight b may be adjusted upward along thepointer, so as to afiord less resistance to the deflection of thepointer and vice versa.

What I claim is The combination, with an ammeter, of the terminals E E,connecting-plug E and connecting-links E whereby the line may be closed,and the instrument removed or adjusted without disturbing the terminals,substantially as described.

In testimony whereof I sign this specification in the presence of twoWitnesses.

JOSEPH E. LOCKIVOOD.

Witnesses:

CHAS. P. LARNED, L. A. DOELTZ.

